The catastrophic extinction of NorthAmerican mammoths andmastodonts

Gary Haynes

Abstract

Archaeological and theoretical evidence reviewed here indicates that Clovis-era foragers extermi-nated mammoths and mastodonts in North America around 11,000 radiocarbon years ago. Theprocess unfolded quickly as human foragers explored and dispersed into fragmenting habitats wheremegamammal populations were ecologically stressed. Megamammal extinctions were eco-catastro-phes with major ripple effects on �oral and faunal communities.

Keywords

Mammoth; mastodont; extinction; Palaeoindian; North America; patch choice.

Introduction

Mammoths and mastodonts became extinct in North America soon after 11,000 radio-carbon years before present (RCYBP) (Taylor et al. 1996; Martin and Stuart 1995; Stuart1991). Thirty-three genera of large mammals (body mass over 44 kg) died out around thesame time (Martin and Klein 1984). Distinctive Clovis �uted projectile points (Plate 1)also appeared then (see the papers in Bonnichsen and Turnmire 1991). Prehistorians suchas C. V. Haynes, Jr. [who is not related to me] have proposed that �uted point assem-blages represent North America’s earliest archaeological culture because they are theoldest found at virtually every site, locale or subregion where they have been dated. Theexceptions are few, such as in Alaska’s Tanana river valley sites (Hamilton and Goebel1999) or in scattered locales such as Cactus Hill, Virginia (McAvoy and McAvoy 1997)and Meadowcroft Rockshelter, Pennsylvania (Adovasio et al. 1999). But examples of pre-�uted-point components are extremely rare (Fiedel 2000). The people who made theClovis-type �uted points are incontestably the �rst to arrive in most parts of late Pleisto-cene North America, and therefore are closely linked chronologically with the disap-pearance of mammoths and mastodonts.

World Archaeology Vol. 33(3): 391–416 Ancient Ecodisasters© 2002 Taylor & Francis Ltd ISSN 0043-8243 print/1470-1375 online

DOI: 10.1080/0043824012010744 0

We know that human hunting can limit or exterminate ungulates with or withoutclimate stress (Alroy 2000; Kay 1994, 1995; Martin 1967, 1982, 1984, 1990; Martin andSteadman 1999; Mithen 1993; Stuart 1999). If the �rst settlers in North America targetedlarge mammals as preferred prey, their opportunistic foraging (Kelly and Todd 1988;Meltzer 1993: 305) may have eradicated mammoth and mastodont populations that hadsurvived earlier cycles of ecological stress during rapid climatic oscillations (Alroy 1999;Martin and Steadman 1999).

The removal of mammoths and mastodonts from the New World was an eco-catastrophe that happened swiftly and unexpectedly. Fossils of large mammals show noevidence of climate-caused chronic ill-health or increased vulnerability just before theydisappeared (see, for example, Fisher (1996) for information about mastodonts andDuckler and van Valkenburgh (1998) for information about predators). The largemammals – including mammoths and mastodonts – were exterminated so quickly that thegeological record provides no direct clues about how it happened.

The disappearance of America’s largest forms of animal life would have been a memo-rable event for humans to experience. As well, the disappearance of animals large enoughto be true ‘ecosystem engineers’ (see Owen-Smith 1987, 1988, 1999) would have hadprofound effects on North American ecosystems. Owen-Smith (1987, 1999: 67) has arguedthat the extinction of megamammals – the animals weighing over 1,000 kg – transformeda minor extinction pulse affected by climate change into a major extinction cascade,because mammoths and mastodonts were ‘keystone’ species that had greatly raised diver-sity at the patch level. With the megamammals gone, natural processes such as woodyregeneration and shrub invasions of grassy glades progressed unimpeded, thus reducingcarrying capacity for nonmigratory grazers.

Zimov et al. (1995) presented a simulation model showing that the removal ofBeringia’s megafauna by human overhunting was as important as climate in shifting thevegetation from highly productive, grass-dominated steppe to poorly productive moss-tundra. Large herbivore feeding has major effects on ecosystems and is known to increaseprimary productivity in African grassland savanna (Bell 1971), an effect also postulatedfor California grasslands (Edwards 1992). The process of biome shift due to herbivore

392 Gary Haynes

Plate 1 Fluted point (cast) from the Vail site in Maine. Fluted pointscompared over space and time may differ in morphology and manufacturingtechniques.

feeding is now being observed in Yakutia, where large grazers were recently re-introducedinto tundra-taiga habitats that may be transformed to steppe in the future (Stone 1998;Zimov et al. 1995: 782–3).

lf human foragers did wipe out mammoths and mastodonts in North America and indi-rectly caused the extinctions of other animal species, can we ever discover why and howthey managed to do it? My explanation of the process is founded on three propositions:(1) the timing and direction of climate-caused habitat changes were not coupled withextinctions; (2) megamammals were demonstrably killed by human hunters in NorthAmerica; (3) late Pleistocene foraging in mammoth and mastodont ranges was an optimalstrategy for opportunistic hunter-gatherers. These will now be discussed.

Climate-caused changes in habitat were not coupled with extinctions

At the end of the Pleistocene, severe climate reversals occurred out of phase with theextinction event. The Younger Dryas chronozone – a northern hemisphere geologicalinterval of cold that had abruptly reversed warm and wet conditions beginning around11,000 RCYBP and ending nearly a millennium later (duration and timing are problemati-cal in different world areas (Rutter et al. 2000)) – is sometimes thought to have been thelast straw for larger mammals, killing them off completely after they had suffered throughseveral cold to warm reversals following the last Glacial Maximum.

Yet the current best-guess chronosequence of events during the glacial to deglacial tran-sition (for example, Fiedel 1999: 106, �g. 6) does not support this scenario of extinctionbased solely on climate. The earliest appearance of foragers who made Clovis �utedpoints was about 11,500 RCYBP (Fig. 1). Some large mammals may have become extinctaround 11,200 RCYBP, followed by a near-continental drought beginning 10,900 RCYBP,and the extinctions of all large fauna including mammoths and mastodonts by around10,800 RCYBP (Graham et al. 1997; Stafford et al. 1997a, 1997b; Holliday 2000; Haynes, C.V. 1991). The Younger Dryas reversal to cold conditions may not have occurred every-where, and, where it did occur, it followed some extinctions but preceded mammoth andmastodont extinction. In southern South America there may have been no Younger Dryasat all (Bennett et al. 2000; Rodbell 2000), and thus the New World pattern of extinctionsis not a direct result of the abrupt onset or end of the Younger Dryas. It is worth notingagain that megafauna such as ground sloths, horses, camels, mammoths and mastodontshad universally survived earlier abrupt climate reversals.

No clear model can explain how the extinction process tracked changes in climate andhabitat at the end of the Pleistocene (see Krech 1999: 38–40 for a précis of the ambigu-ity). But the extinctions do seem to be synchronous with the existence of human foragerswho dispersed through the continent within a few centuries of �rst appearing.

The Clovis foraging strategy involved killing megamammals

The makers of Clovis-like �uted points were present over almost all of North Americasouth of the last glacial ice-fronts, between around 11,500 and 10,500 years ago (Table 1).

Catastrophic extinction of mammoths and mastodonts 393

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A small but in�uential literature has argued that Clovis �uted point makers were big-gamehunters, directly descended (biologically and culturally) from Eurasian Upper Palae-olithic steppe explorers (see, for example, Haynes, C. V. 1987). Scholars who accept thisprobable connection nevertheless recognize that smaller game and plant resources alsowould have been eaten (Jennings 1989; Willey 1966).

On the other side of the debate are arguments that only plants and small animals wereregularly targeted as food, in direct proportion to their existence in Clovis-era habitats(Dent 1995; Dincauze 1993: 285; Meltzer 1993; Meltzer and Smith 1986). The hypothesisthat Clovis foragers were mainly plant-food gatherers and smaller-game hunters impliesthat Pleistocene large mammals were either hunted extremely rarely, especially if popu-lations were dwindling due to climatic stress (Webster and Webster 1984), or were deliber-ately avoided. The sites where Clovis tools are associated with megamammal skeletons(see below) are therefore considered more likely the evidence of scavenging rather thanof killing.

However, a comparison of the characteristics that distinguish killing from scavenging(Haynes, G. 1999) indicates some Clovis mammoth associations are cases of actualkilling, after all. The basis for comparisons are studies of contemporary bonesites whereAfrican elephants were either shot to death or starved during droughts in Zimbabwe

Catastrophic extinction of mammoths and mastodonts 395

Table 1 Generally accepted radiometric dates on Clovis-point sites (from Holliday 2000; Haynes,C. V. 1993; Taylor et al. 1996).

Site Date(s) Material dated

Anzick, MT Average of 3 = 10,820 ± 60 BoneAubrey, TX Average of 2 = 11,570 ± 70 CharcoalClovis type site Average of 2 = 11,130 ± 90 Plant remains(Blackwater Draw, NM) Average of 3 = 11,300 ± 240 Plant remainsColby, WY 11,200 ± 220(RL-392) Bone apatite

10,864 ± 141 (SMU-264) Bone collagenDebert, Nova Scotia Average of 13 = 10,590 ± 50 CharcoalDent, CO Average of 5 = 10,690 ± 50 Bone

plus 11,200 ± 500 Domebo, OK Average of 2 = 10,820 ± 230 Carbonized plants

Other averages 11,040 ± 250 Bone collagen and gelatinand 10,940 ± 180 Bone collagen and gelatin

Lange/Ferguson, SD 11,140 ± 140(AA-905) Charcoal10,730 ± 530 (I-13104) Bone collagen

Lehner, AZ Average of 12 = 10,930 ± 40 CharcoalMurray Springs, AZ Average of 8 = 10,900 ± 50 CharcoalShawnee-Minisink, PA Average of 2 = 10,640 ± 90 Charcoal

Average of 2 more = ~10,900 Charred hawthorne plum seedsTempleton, CT 10,190 ± 300 (W-3931) CharcoalVail, VT 7 dates, 11,120 ± 180 All but one on charcoal;

to 10,040 ± 390 youngest date on humatesWhipple, NH Average of 2 = 11,050 ± 300 Charcoal

(2 other parts of the site were (Charcoal)dated 9,400 ± 500 to10,430 ± 300)

(Haynes, G. 1987, 1988, 1989, 1991). The modern sites are similar in some ways butdistinct in other subtle ways (see Haynes, G. 1999; Haynes, G. and Eiselt 1999) (Table2). If bone representation, weathering stages, carnivore utilization and mortality pro�lesare compared between cultural killsites and noncultural deathsites, the modern sites ofelephant bones differ to perceptible degrees when their origins differ. The presence orabsence of artifacts is not the de�ning characteristic that sets apart cultural and noncul-tural deaths.

An examination also has been made of Columbian and woolly mammoth bone assem-blages (Haynes, G. 1999). The differences among the sites suggests unambiguously insome cases and ambiguously in others that human behavior created certain sites andnatural (noncultural) processes created others, even those with clearly associated arti-facts. This evidence does therefore support the idea that Clovis foragers actually killedmammoths individually or in groups.

Empirical and analogical approaches to explaining the role of megamammals in Clovisdiets

Opinions differ about Clovis subsistence and diet because the methods of reconstructingthe possible diet of �uted point-makers rely on three distinct lines of evidence: empiricaldata, ethnographic analogy and theoretical predictions. The three approaches producedifferent interpretative results.

(a) Empirical evidence Plant and animal remains are scarce at Clovis �uted point sites.Yet at least twenty sites contain mammoth or mastodont bones (Table 3) either directlyassociated with �uted points or interpreted as butchered during the Clovis period. Theremains of animals other than proboscideans in direct stratigraphic and spatial associationwith �uted points are less abundant (Table 4). Many sites contained no more than teethor a single element or bone fragment of camel, caribou or other large mammal. Several

396 Gary Haynes

Table 2 Comparison of cultural and noncultural elephant bone accumulations.

Serial deaths onlyVariable examined Cultural origin Noncultural origin

Carnivore use Often light VariesWeathering Mixed MixedBone representation Selective NonselectiveAge pro�le Varies Selective

Mass deaths onlyVariable examined Cultural origin Noncultural origin

Carnivore use Light to moderate Light to moderateWeathering Mostly similar Mostly similarBone representation Nonselective NonselectiveAge pro�le Nonselective Selective

studies have been interpreted to indicate that large mammal blood, including that ofmammoths, was present on some �uted points (Table 5).

Hence, the evidence for megammamals in the Clovis diet is ample, but the evidence forfood items other than megamammals is scarce. Botanical macrofossils are even more rare

Catastrophic extinction of mammoths and mastodonts 397

Table 3 Mammoth (Mammuthus columbi) and mastodont (Mammut americanum) sites with Clovisassociation, or dated to the Clovis time interval. (Note: Fisher (1996) names other late Pleistocenemastodonts he considers butchered by humans in the Great Lakes region, but here I list only two,Heisler and Pleasant Lake in Michigan.)

Site Taxon and number Cultural association/dateof animals present

Blackwater Draw, NM Mammoth, 6 Clovis lithics; averaged 3 dates 11,170 ± 110Burning Tree, OH Mastodont, 1 No lithics, possibly butchered bones; 10,860 ±

70 (Pitt-0832) and 11,390 ± 80 (AA-6980)Colby. WY Mammoth, 7 Clovis lithics; 11,200 ± 220 (RL-392) and

10,864 ± 141 (SMU-254)Dent, CO Mammoth, 13 Clovis lithics; averaged 5 dates 10,690 ± 50, and

11,200 ± 500Domebo, OK Mammoth, 1 Clovis lithics; averaged 2 dates 10,820 ± 270Dutton, CO Mammoth, 1 Clovis lithics; <11,710Escapule, AZ Mammoth, 1 Clovis lithics; no dateHeisler, MI Mastodont, 1 No lithics, possibly butchered bones; 11,770 ±

110 (NSRL-282, AA-6979)Hiscock, NY Mastodont, 6 Clovis lithics; 11,390±80 (AA-6977) to 10,515 ±

120 (Beta-24412)Kimmswick, MO Mastodont, 2 Clovis lithics; no dateLange-Ferguson, ND Mammoth, 2 Clovis lithics; 11,140 ± 140 (AA-95) and 10,730

± 530 (I13104)Lehner, AZ Mammoth, 13 Clovis lithics; averaged 12 dates 10,930 ± 40Leikum, AZ Mammoth, 2 Clovis lithics; no dateLubbock Lake, TX Mammoth, 2(?) Clovis lithics; >11,100Miami, TX Mammoth, 5 Clovis lithics; no dateMurray Springs, AZ Mammoth, 2 Clovis lithics; averaged 8 dates 10,970 ± 50Naco, AZ Mammoth, 1 Clovis lithics; no dateNavarettej AZ Mammoth, 1 2 Clovis points; no datePleasant Lake, MI Mastodont, 1 No lithics, possibly butchered bones; 10,395 ±

100 (Beta-1388)Rawlins, WY Mammoth, 1 Untyped lithics; 11,280 ± 350 (I-449)(U.P. mammoth)

Note: Occasionally other megamammal �nds with possible Clovis associations have been datedradiometrically well older or younger than Clovis. These examples can be partly explained by thenature of radiocarbon dating – ‘dates’ are only a statistical probability of an object’s age and not asimple ‘fact’ – or by the potential for sites, sediments and samples to be contaminated, or by inappro-priate choices of materials to be dated, or by ‘associations’ that are speculative rather than clearlydemonstrated, etc. At least one-half of all radiocarbon dates returned over the past half-centuryprobably have been rejected or suppressed because of suspected errors. This may make readersnervous that the real dates of Clovis and megamammal extinction could be quite different from the11,500–10,500 radiocarbon years generally accepted. However, when samples are carefully collectedand lab protocols followed, the dates much more often come out within the generally expected timeinterval (see Stafford 1988; Stafford et al. 1987, 1988).

398 Gary Haynes

Table 4 Sites with possible associations of Clovis artefact(s) and animals other than mammoth ormastodont. ‘Clovis lithics’ refers to assemblages containing both Clovis �uted points and other stoneimplements. Not all taxa in the table should be considered food items, and many may be ‘back-ground’ accumulations. Many taxa were represented by only small numbers of bones or teeth. Somesites contained mammoth or mastodont bones, too.

Site Cultural association Taxa

Aubrey, TX Clovis lithics Deer, bison, rabbit, muskrat, �shes, birds,turtles, rodents, ground sloth (skin only)

Blackwater Draw, NM Clovis lithics Bison, horse, camel, box turtleBull Brook, MA Clovis lithics Caribou, beaverColby, WY Clovis lithics Hare, pronghorn, ass, camel, bisonEscapule, AZ Clovis points HorseHiscock, NY Clovis points Caribou, moose/stag-moose, California

condor, grebeHolcombe, MI Clovis lithics CaribouKimmswick, MO Clovis lithics Micromammals (mainly rodents)Lehner, AZ Clovis lithics At least 11 taxa, incl. micromammals, and

horse (teeth), camel, bisonMurray Springs, AZ Clovis lithics Numerous taxa, incl. micromammals, and

horse (teeth), camel, bisonNaco, AZ Clovis points BisonShawnee-Minisink, PA Clovis lithics Fish, micromammals and reptilesSheriden Cave (or Pit), OH Clovis lithics Turtle, caribou, peccary, giant beaver

(Holcombe-like point)Udora, Ontario Nondiagnostic cached Cervid, hare, arctic fox

lithics, plus nearbysurface Clovis(Gainey?) points

Whipple, NH Clovis lithics Caribou

Table 5 The results of blood residue studies on Clovis tools. 1. Gramly (1991, 1993).2. Hyland et al. (1990); one endscraper out of forty-�ve tested had cervid residue. 3. Dixon (1993);Loy and Dixon (1998). 4. Kooyman et al. (2000). 5. Brush and Yerkes (1996); Brush and Smith(1994); Brush et al. (1994). 6. Molyneaux (2000).

Site (reference) Taxa identi�ed

East Wenatchee (Richey-Roberts), WA (Clovis cache) (1) Human, bison, bovine,cervid, rabbit

Shoop, PA (l endscraper tested in Clovis site) (2) CervidAlaskan �uted points (3) MammothWally’s Beach, Alberta (Clovis points) (4) Bovid, horseMartins Creek, OH [note: not a proven Clovis site; site contains Elephant, cervidmastodont and deer bones associated with �akes and scrapers] (5) Western Iowa (Northern Loess Hills) (6) Cervid

than small animal remains, and thus very few plant foods are known. Nuts, grains, andperennial roots or tubers require special tools and technologies such as milling stones orrock-lined roasting pits, which are virtually nonexistent in Clovis times (Table 6).

Faced with a disappointingly small proportion of sites that indicate anything about diet,some prehistorians bypass the continent-wide empirical evidence and invent site-by-sitediets based on what might have been possible. However, judging only on the basis ofrecovered materials rather than on the basis of possibilities, the logical conclusion is that�uted point makers ate megamammals more frequently than anything else known.

(b) Ethnographic analogy Another argument made against megamammal-hunting byClovis is based on ethnographic literature. There are no known subsistence hunters ofmegamammals in the world nowadays, except for arctic native whalers. In Africa,elephants are still killed by ivory poachers or people seeking both trade items and food(Fisher 1987, 1992; Duffy 1984); but no longer is meat the main reason for killing elephantsin Africa (Sikes 1971: 309–10). Modern subsistence foragers – even those in elephantcountry – target medium and small game, and rely more on plant foods than on gameanimals (Lee 1968; see also Meltzer 1988, 1993). Some archaeologists interpreting Clovissubsistence have relied on ethnographic analogues to develop a line of reasoning thatClovis �uted point makers, like modern foragers, also never or rarely tried to kill mega-mammals, and instead chose to forage for a wide range of smaller game, plant foods andaquatic resources (Dincauze 1993; Meltzer 1988, 1993). Tacit in this argument is the ideathat foragers procure different food resources in the same proportions the resources occurin local environments. Because there are more smaller animals than megamammals interrestrial habitats, more small animals would have been hunted.

Anthropology’s available ethnographic snapshots are of foragers who no longer live ina world of foragers, and they behave differently from foragers who did live in such a world,where the ability to disperse, explore and exploit resources was less limited (for anexample of differences between modern and prehistoric foragers, see Sealy and Pfeiffer2000). One major difference between Pleistocene and recent foragers has been shown ina study of human bones from two late Pleistocene sites in England: analysis of the bones

Catastrophic extinction of mammoths and mastodonts 399

Table 6 Clovis sites with milling stones, roasting pits or other tools/facilities suggesting routine useof nuts, seeds or other plant foods. 1. Hester (1972: 107–9). 2. MacDonald (1968: 111, table 15). 3.Spiess and Wilson (1987); Dincauze (1993).

Site (reference) Artifact/facility present Comments

Blackwater Draw, NM (1) One grinding stone (‘small mano’) Used for pounding andreciprocal grinding; not knownif used for seed preparation or�intknapping

Debert, Nota Scotia (2) Possible processing implements: Suggested use: processing ‘pulping planes, cleavers’ vegetable products for food or

fuelMichaud, ME (3) Possible processing implements: Possibly used for grinding,

cobbles pounding, plant processing

shows that the diet at around 12,000 RCYBP consisted mainly of terrestrial animal meat(Richards et al. 2000), unlike the diet of modern foragers which tends to be mostly plantfoods (see Lee 1968).

Late Pleistocene foraging in North America would have been distinct from the behav-ior of modern foragers in other ways, as well. During the late Pleistocene, megamammalkills would have been naturally refrigerated or frozen for long periods of time and thuswould have ‘kept’ much better than do elephant carcasses in tropical or subtropical Africaand Asia; the preservation would have facilitated a much more ef�cient use of hugecarcasses. Perhaps the convenience of long-term storage encouraged regular hunting ofbigger animals.

Modern-day ethnographic analogy cannot reliably predict Clovis foraging or subsist-ence behavior. Clovis foragers colonized an enormous, highly diverse continent with anextremely low human population density, if it had any humans in it at all. Clovis foragingprobably differed from tropical foraging in so many ways that analogies should not betrusted when reconstructing Clovis diet.

Human nutritional requirements are satis�ed by a great many alternative diets. Spethand Spielmann (1983) demonstrated that high-protein diets (such as from megamammalhunting) require animal fat or carbohydrates to supplement lean meat, otherwise humanswould die from protein poisoning or suffer chronic disease. However, even food-stressedmammoths and mastodonts would have provided relatively large packages of fat andmeat, some of the fat distributed around the meat, some around viscera and some withinbone marrow cavities (Haynes, G. 1991, unpubl. �eld notes 1982–7). Megamammalhunters or scavengers would have eaten adequate fat from each megamammal carcass,and avoided protein poisoning.

Recent optimal hunter-gatherer diets are modeled as healthy mixtures of plant andanimal foods low in fat (Eaton et al. 1997), considered to be an evolutionary ideal. Thusa diet high in megamammal meat and fat may not sound very healthy from the modernperspective, but even a human diet that is ‘high in animal fat and low in vegetable-derivedfoods is not incompatible with [good] health’ (Johns et al. 2000: 458), according to a recentstudy of a non-industrialized society. This study suggests that megamammal-hunterswould not have been plagued by high cholesterol or other potential problems simplybecause they ate minor amounts of plant foods with their mammoth meat, if they supple-mented their diet with select roots, gums, resins or barks that provide antioxidants andblood lipid-lowering phytochemicals (Johns et al. 1999, 2000).

Finally, as a last rebuttal against using ethnographic analogies to reject Clovis huntingof mammoths, I submit that to argue about the impossibility of megamammal huntingbased on the dangers of such a practice is by far the most defective kind of reasoning. Alesson may be learned by reading George Catlin’s eyewitness description of a PlainsIndian buffalo surround which turned into ‘a grand turmoil’ and ‘desperate battle’ (Catlin1989 [1844]: 196, 197) between Minataree hunters and ‘infuriated’ buffalo: unhorsed menran for their lives in front of pursuing bulls, and hunters leapt from their horses onto thebacks of thronging buffalo to escape a crush. These explosive activities were regularoccurrences for native American buffalo hunters. Clearly the Minataree hunters Catlinwatched were courageous beyond the limits that archaeologists �nd in themselves. Like-wise, few if any archaeologists will venture into Arctic waters in a skin boat to go whaling,

400 Gary Haynes

armed with only throwing-boards and harpoons, but arctic native peoples often did so(Yesner 1980), knowing full well the risks. As a native whaler from the Chukotka regionof Russia told Makah whaling captain Wayne Johnson, ‘Not everyone’s going to comehome all the time [from a whale hunt]’ (Sullivan 2000: 52).

Killing megamammals was optimal foraging at the end of the Pleistocene

The marginal value theorem has been mistakenly interpreted to predict that disappear-ing species would not have been hunted since they were harder and harder to locate(Webster and Webster 1984; Meltzer and Smith 1986). Based on this reasoning, and takinginto account the ethnographic snapshots of foraging behavior mentioned above, an argu-ment has been made that �uted point makers did not preferentially hunt mammoths andmastodonts.

However, the marginal value theorem (MVT) does not directly predict that foragersreduce their value ranking of a dietary item based exclusively on that item’s scarcity(Charnov 1976; Winterhalder 1981). What the MVT does predict is how foragers evalu-ate the time spent in a patch looking for food before leaving to seek food in other patches(Fig. 2). Studies of modern foragers show that patch-residence time may increase duringperiods of climate change, gradual overhunting or forager population growth, because,once foragers become aware that prey abundance is falling, they no longer see goodreasons to seek another patch whose prey abundance is also likely to be dropping. Hence,prey depletion may continue in the very patches where hunting pressure is already high(see Smith and Wishnie 2000). Foragers under these and other conditions make subsist-ence decisions to maximize the harvest of energy per time spent foraging, in spite of poss-ible depletion effects on prey, because pro�tability is the routine goal of foraging – evenwhen it furthers prey depletion (Smith and Wishnie 2000).

Mammoths and mastodonts were highly ranked food resources whose presence couldbe plainly predicted in speci�c ranges, and whose condition and health could be moni-tored by �uted point makers. The presence and the health of megamammals are recordedthrough observations of the animals and the abundant signs left by them. Like elephants,mammoths and mastodonts would have been great trailmakers and sign-leavers (Plate 2).Modern research on elephants in the wild often relies on studies of dung and other signsto provide data about elephant numbers, diets and health, and the proportions of animalsof different ages and sexes (Barnes and Jensen 1987; for examples, see De Boer et al. 2000;Theuerkauf and Ellenberg 2000). Prehistoric foragers would have been skilled trackersand interpreters of the megamammal landscape.

Food ranking by foragers re�ects more than a food item’s abundance – it re�ects energyreturn, handling time, reliability, and risk minimization. Certainly Clovis foragers did under-stand how scarce big animals may have been, but this was not the primary consideration whendeciding to hunt them. Slow-reproducing resources whose local replacement in patches isperceived as lower than the rate of return from foraging in general will still be harvested,even at unsustainable rates (Clark 1973; Alvard 1998). Although search time may be high,larger animals are rationally ranked highly due to the promise of rich return. For example, a4,000kg mammoth would have returned about 5,000,000 Kcal of energy (calculated based on

Catastrophic extinction of mammoths and mastodonts 401

a ratio of 30 per cent body mass salvaged by butchering, and an average value of 4 Kcal pergram of meat [protein]). The next largest mammal of the times, bison, would have returnedonly a quarter of this amount, but may have been no less dangerous to attack. Instead ofspending three days hunting down and processing a bison, optimizing foragers might havechosen to spend twelve days �nding and processing one mammoth.

Foragers continually evaluate the potential returns from the animals encountered and– as has been demonstrated empirically – reasonably rank the bigger ones highly, if thereis a chance of successfully procuring them. Foragers such as those of the late Pleistocene,who were capable of killing megamammals throughout their ranges, would not haveavoided killing mammoths or mastodonts when encountered, even though these animalswere not always relatively abundant or evenly distributed in their ranges.

Pleistocene foragers evaluated their food returns patch-by-patch in the same manneras do foragers in modern times – by reference to average returns from all destinationpatches (Fig. 2; see Giraldeau 1997). Prior information about resources, prey and theenvironment is used in making foraging decisions, and the more promising patches aresearched for longer times than poorer patches, especially if they are widely separated. If

402 Gary Haynes

Figure 2 Marginal value theorem (redrawn from Charnov 1976). The chart shows graphically thata forager who travels a long time to get to a patch will probably decide to stay longer in the patchthan a forager who travels a short time. The decision about how long to stay is made based on thepatch’s rate of return compared to the average rate of return for all patches.

the richer patches also happened to be the places where megamammals aggregated, thesepatches would have remained attractive to foragers for relatively long spans of time.

A strategy for reducing search time would have been apparent to foragers in the latePleistocene, if megamammal behavior resembled that of modern megamammals such aselephant and rhinoceros. Foragers of the late Pleistocene, in order to minimize risk, toincrease encounter rates, to reduce pursuit time, and to limit their foraging radius, there-fore would have actively sought out the very patches where megamammals aggregated.

A tremendous advantage that humans have over other animal foragers is that they areomnivorous – they could have comfortably survived in any season by eating a wide varietyof other foods while continuing to search for the preferred megamammal prey, even after

Catastrophic extinction of mammoths and mastodonts 403

Plate 2 An elephant trailin Kalahari sands ofAfrica. Trails are richsources of informationabout animal numbers,health and behavior, plusthey make exploratorytravel by human foragerseasier and less risky.

mammoths and mastodonts had become scarce due to climate change and overhunting(Owen-Smith, N. 2001 pers. comm.).

If �uted point makers (1) did hunt megamammals, (2) did not avoid hunting them whenextinction began to occur and (3) ate megamammals more than other animal and plantfoods, what could be concluded about their continent-wide subsistence preferences? Theanswer would be that Clovis people preferred to hunt mammoths and mastodonts, andthat as foragers their mobility strategies were intended to increase the chances of encoun-tering these megamammals. In other words, in this model Clovis subsistence was anopportunistic specialization in proboscideans.

Foraging specialization in a few, preferred resources is a viable strategy when preydiversity is low, and prey tend to aggregate in herds that feed nomadically. In the lastdeglaciation interval, the largest mammals were distributed non-randomly in differenthabitats. Not only were megamammals found in clustered aggregations, but they also werere-ordering their range distributions as climatic changes forced �oral communities tochange their spatial extents and distributions. The main changes in vegetation involved areduction in mosaic cell sizes (discussed below) or the areal extent of different �oralcommunities contacting each other.

Patch dynamics in the late Pleistocene

At the end of the Last Glacial Maximum (LGM) many of the once associated animalspecies radically (and individually) rearranged their geographic distributions in responseto changing climatic factors (Graham and Lundelius 1984; Graham et al. 1996). Somespecies retreated south, some retreated north and some changed their elevational distri-butions. Thus ended the existence of Pleistocene ‘mosaics’ of mixed species that do notlive together now.

In many parts of North America the areas of Pleistocene plant mosaics became moreand more separated from each other (King and Saunders 1984), as a result of the post-LGM establishment of broad zones of uniform vegetational types, where biotic diver-sity was much diminished. The last mosaic areas (woodland abutting steppe nearshrubby taxa, for example) had a very reduced distribution at the end of the Pleisto-cene, particularly in localities such as southeastern Arizona, southern Nevada, centralMexico, the Great Lakes region, parts of the Ohio river drainage in Kentucky, andalong the limestone-lined floodplains of the Mississippi river in Missouri, all of whichare rich fossil-collecting regions that used to be late Pleistocene refugia. The wordrefugium here is used in the sense of ‘an isolated habitat that retains the environmentalconditions that were once widespread’ (Lincoln and Boxshall 1987: 326) and is not thesame as ‘refuge’, which refers to space where predators can be avoided (Lincoln andBoxshall 1987: 326).

Keystone megamammals in refugia kept biotic diversity relatively high, due to themajor impacts of their feeding, trampling and wallowing habits (Laws et al. 1975; Owen-Smith 1987, 1988; Putschkov 1997; Sikes 1971; Western 1991, 1989). Like modernelephants, American mammoth and mastodont populations may have been able to sustaindensities of up to two or three individuals per 2km, greater than most other herbivoresattain (Owen-Smith 1988, 1999). As Owen-Smith has argued, high densities contributed

404 Gary Haynes

to megamammal ecosystem engineering – such as the pruning of woody plants duringfeeding, the enlargement of water holes and mineral licks, and the suppression of �res byopening up vegetation patches.

Hence, once climate changes following the Last Glacial Maximum caused extremeshrinkage of mosaic cells and the wide separation of once-abutting vegetational patches,the diversity and productivity of Pleistocene habitats were dramatically changed. Eachdifferent type of cell became isolated, greatly reduced or eliminated. Fewer patches ofrich ecotones survived over time. The ranges of grazing and browsing animals were widelyseparated from each other, except in the refugia which continued to provide a variety ofpalatable and preferred forage (Fig. 3). Around 11,000 RCYBP, biotic responses to climatechange occurred within even shorter spans of time than before, swiftly destabilizingecosystems (Ammann et al. 2000).

Other climatic/palaeoenvironmental trends also served to cluster and isolate the largest

Catastrophic extinction of mammoths and mastodonts 405

Figure 3 Schematic map showing two diverse mosaic environments separated by zonal vegetationthat herbivores �nd unpalatable or unpreferred. Terminal Pleistocene refugia may have beenmosaics like these.

terrestrial mammals at the end of the Pleistocene. A Clovis-era drought of about 10,900to 10,650 RCYBP (Haynes, C.V. 1993, 1991) or slightly later (Holliday 1997, 2000) forcedmammoths and other large mammals to congregate at a much reduced number of sourcesof water and forage (see Haynes, C.V. 1984, 1991) in the American West and possiblyother regions. Research in the mid-continental Great Lakes region similarly indicates thatterminal Pleistocene refugium patches existed there, too, providing either better food,more of the essential dietary minerals or some other requirement in quantities or qualityhigher than in the surrounding regions (Dreimanis 1967; Fisher 1996). The Hiscock sitein northern New York state (Laub 1994; Laub et al. 1988, 1994) contains evidence oflowered water table at the time mastodonts were dying-off there (c. 10,800 RCYBP.). Wellswere apparently dug by mastodonts seeking clean water; tusk-tips were broken off during�ghts over access to the wells (Laub and Haynes 1998; see Haynes, G. 1991: 126–31). Thelowering of water tables resulted either from drought or from changes in Great Lakeshydrology, as the Lakes switched drainage between the St. Lawrence and the Mississippiriver systems during deglaciation. At this same time, in the southern part of the continentalong the coastal plain adjacent to the continental shelf– such as in Florida – water tablesrose as sea levels came up, but the addition of so much water to relatively �at land surfacescreated stresses similar to the removal of water in other regions, as the plant foragedrowned or died from waterlogging.

Thus ecological stresses and selective disadvantages existed in mammoth andmastodont populations during the dif�cult time following the Last Glacial Maximum, andthe stresses intensi�ed after 11,000 RCYBP due to rapid climatic reversals, increasedseasonality and extremes of seasonal climate patterns, and a severe reduction of preferredhabitats. Similar disadvantages can be seen in recent �eld studies of large mammals infragmented and crowded ranges (Owen-Smith 1982, 1988; Rachlow 1997; Rachlow et al.1998). Large mammals suffer from (1) increased incidence of oftentimes violent agonis-tic encounters; (2) heightened feeding competition leading to mortality of youngestanimals �rst; and (3) differential reproductive success, as some males successfully breedbut others do not, resulting in a reproduction rate much lower than predicted based onnumbers of animals alone.

Yet, climate change and resultant stresses could not have been the cause of all extinc-tions. Megafaunal taxa during the Pleistocene partitioned resources and had stereotypeddiets. For example, the Florida mastodonts were browsers while mammoths were grazers,a conclusion based on geochemistry, habitat reconstructions and the obvious differencesin tooth morphology (Hoppe et al. 1999; Koch et al. 1998). Animals with different stereo-typed diets were not uniformly affected by the vegetational changes resulting from thelate Pleistocene climate oscillations. Some animals suffered from disappearing forage, butother taxa were favored by changes in plant distributions. For example, Florida’s wood-lands did not disappear at the end of the Pleistocene, but its browsing mastodonts did,and it is dif�cult to explain these out-of-phase phenomena without invoking some agentof mastodont extinction other than habitat change. The late Pleistocene was hard onmammoths and mastodonts, yet no compelling evidence exists from the very end of thePleistocene that both mammoth and mastodont populations suffered greater stress thanthey had during earlier climatic oscillations.

Megamammals were not just circling the drain before they went down the plughole of

406 Gary Haynes

extinction, although they were less abundant than they had been earlier. How did Clovisforagers respond to the changes in proboscidean vulnerability, distribution, density andbehavior? Under the palaeoenvironmental conditions of the end of the Pleistocene, the�uted point makers preferentially began to hunt megamammals, seeking them outthrough patch choices that targeted refugia and high-diversity ecotones. Under theconditions of the end of the Pleistocene, megamammal-aggregation locales would havebeen preferentially sought for foraging.

Clovis ecology, diet and mammoth-hunting

At the level of the entire continent, �uted point makers hunted mammoths andmastodonts in the remnant megamammal refugia. As presented here, a model of contin-gent causality explains �uted point subsistence, settlement and dispersal in terms of latePleistocene climatic change, palaeoenvironmental developments, megamammal behav-ioral patterns and rational foraging decisions. The necessary and suf�cient causes wereserial in occurrence:

The �rst event A was the climate-driven changing of late Pleistocene habitats, creatingisolated refugium patches for megafaunal populations. Early human foragers who huntedmedium to large animals such as camels or horses found them easier to locate and kill.Clovis technology – blades, bifaces and �uting – developed under changing ecologicalconditions.

Event B was the exploratory dispersal of �uted point makers into ranges wheremammoths and mastodonts could be found. Resources were predictable in certainpatches, and the technology created in response included well-prepared and sturdy tools.Long-distance import of high-quality raw materials raised the cost of the technology, butthe practice of lithic caching helped reduce the high costs of tool transport. Megamam-mals were preferred prey; niche width was narrow, since diet breadth was deliberatelyreduced. Risks were minimized over the long and short terms. The ability to explore anddisperse into new ranges was unlimited.

Event C was the intensi�ed hunting (and scavenging) of mammoths and mastodonts,along with even wider exploration and dispersal. Overall, the foraging ecology of the �rst�uted point makers was continentally almost uniform, but the uniformity was overlain byregional and local variability.

After megamammals became extinct, a new strategy was devised by human foragers.Resources had become less predictable, and new patches and food resources had to befound through far less exploration. Lighter-weight tools were manufactured in someregions, designed to be functionally �exible and generalized. Diet breadths were muchwider. This strategy served better in Holocene zonal habitats and the closed woodlandsof the eastern continent.

The colonization eco-catastrophe: extinction of megamammals

In summary: (1) Megamammals were ranked very highly for inclusion in the diet of �utedpoint makers. Several factors interacted to encourage high ranking: (a) prey body size was

Catastrophic extinction of mammoths and mastodonts 407

large, promising hunters huge nutrient returns; (b) migration trails created by mega-mammals in all likelihood were clear, abundant and �rmly established in megamammalranges, thus prompting human travel and exploration along the same trails thatmammoths, mastodonts and many other mammalian species traveled; (c) late Pleistoceneclimatic changes had comprehensive ill-effects on megamammal behavior and biology,working to the advantage of predatory human groups (cf. also Stuart 1991).

(2) Late Pleistocene refugia were actively sought by Clovis people who used mammothand mastodont trail networks, and were visited either serially or sequentially. By seekingthe refugia along established animal trails, �uted point makers provided themselves acost-reducing and risk-minimizing tactic that supported dispersal widely but safely, andlessened the uncertainties of exploring unfamiliar territory so quickly. It is also conceiv-able that human foragers widened their exploratory abilities and improved their foragingsuccess by establishing partnerships with other hunters and scavengers, such as ravens orwolves, as they learned how to locate each other and discovered new clues pointing tohidden game or scattered carcasses (see, for example, Heinrich 1991, 1999).

Megamammals were pursued when encountered and were killed or scavenged. Theempirical and analogical evidence from major sites supports the interpretation that actualkilling of mammoths and mastodonts took place both serially (over short time spans) anden masse (Haynes, G. 1999). Mithen (1993) computer-modeled mammoth predationunder a variety of environmental conditions and showed that even relatively low levels ofkilling by humans would eradicate mammoth populations. The special point I am makinghere is that hunting pressures by humans were more than merely minimally suf�cient totrigger extinctions, and that, in the absence of human hunting, mammoths and mastodontswere capable of recovering from the habitat changes, as they had done during earlierclimate-change intervals.

(3) Fluted point foraging was not a ‘generalist’ strategy. It was specialized, meaning thatniche width was preferentially narrow. However, diet breadth was rationally determinedfrom site to site, and prey switching undoubtedly occurred when necessary. As alterna-tives to megamammals, other foods such as small animals, plants, and aquatic resourceswere procured after active searching, although less readily than the higher-ranked largemammals.

Once mammoths and mastodonts were removed from North American ecosystems,several critical ripple effects would have been seen in ecosystems. First, the New Worldlost its best trailmakers, whose trail networks had linked optimal resource areas withinecozones and connected the different zones themselves across the entire continent. Manyanimal taxa would have followed these trails, including migrant foraging humans. Thetrails linked water sources, fruit and mast patches, mineral licks and optimal feeding tractswhere other ungulates also fed.

Second, megamammals had pruned woody vegetation around wetlands and streamvalleys, thereby incidentally increasing biotic productivity. Megamammals would havetrampled back encroaching woody plants around meadows and grassy glades, keeping theopen vegetation available for nonmigrating grazing mammals. Proboscideans probablyhelped create grassy glades where nonmigrating feeders congregated (Guthrie 1984;Owen-Smith 1987, 1999). Of the taxa that became extinct at the end of the Pleistocene,many were nonmigrating grazers and browsers of open country (Owen-Smith 1999). After

408 Gary Haynes

herbivore numbers dropped and the woody plants increased, larger-scale �res would havebecome more frequent, further altering American ecosystems on the patch-scale level andabove.

Megamammals had many other deep effects on ecosystems. They had deepened andexpanded ponded water sources, mineral licks and seepage springs through trampling,digging and wallowing. After extinction, these types of sites would have been much moreprone to in�lling through colluvial and alluvial processes, thus reducing surface waterpoints. Megamammal dung had nourished millions of insects, but after the extinction ofmammoths and mastodonts, some species of dung beetle disappeared (Stock 1972). Mega-mammals had carried large and small seeds in their guts and helped disperse numerousplant taxa by passing the seeds in dung. After extinction, many species of plants changeddistribution in response to the loss of such dispersal vectors (Janzen and Martin 1982; alsosee Barlow 2001; Dudley 1999). And megamammal carcasses and bones had fed numer-ous taxa of carnivorous predators and scavengers, including large mammalian species suchas dire wolf (extinct Canis dirus), avian species such as teratorn (extinct Teratornis merri-ami) and condors (extinct Gymnogyps amplus, extinct Breagyps clarki), and arthropodssuch as blow�y (extinct Protocrysomyia howardae) (Harris and Jefferson 1985; Stock1972). After megamammal extinction, these species and others began dying out due to asevere reduction in food supply.

Ongoing analyses of the extinct Pleistocene taxa (Stafford et al. 1997a, 1997b; Grahamet al. 1997) may soon indicate which genera disappeared �rst from sampling locales, butmore dates are needed on well-preserved bones recovered in controlled contexts, andmuch more stringent control of the laboratory processing is necessary to ensure that bonechemistry is clearly known and lab pretreatments are comparable (Stafford 1988, 1999,2000 pers. comm.). If it is ever shown that mammoths and mastodonts survived in NorthAmerica longer than the other large herbivores and carnivores, then the proposed rippleeffects of removing proboscideans will have to be rethought. But currently the radio-metric data indicate that all of North America’s largest land mammals became extinctvery near 11,000 RCYBP. Human foragers in late Pleistocene North America huntedmammoths and mastodonts, and this hunting led to the dying out for ever of those mega-mammals.

Acknowledgements

I am grateful to Paul Martin, Norman Owen-Smith and Janis Klimowicz for reading draftsof this paper and suggesting improvements. I alone am responsible for shortcomings. TheZimbabwe Department of National Parks and Wildlife Management has supported myresearch on megamammal landscapes over the past twenty years, for which I am verythankful. I also thank Adrian Lister for suggesting my name to Peter Rowley-Conwy,editor of this collection of papers about eco-catastrophes.

Anthropology Department (096), University of Nevada, Reno

Catastrophic extinction of mammoths and mastodonts 409

References

Adovasio, J. M., Pedler, D., Donahue, J. and Stuckenrath, R. 1999. No vestige of a beginning norprospect for an end: two decades of debate on Meadowcroft Rockshelter. In Ice Age People of NorthAmerica: Environments, Origins, and Adaptations (eds R. Bonnichsen and K. L. Turnmire).Corvallis, OR: Oregon State University Press for the Center for the Study of the First Americans,pp. 416–31.

Alroy, J. 1999. Putting North America’s end-Pleistocene megafaunal extinction in context: large-scale analyses of spatial patterns, extinction rates, and size distributions. In Extinctions in NearTime: Causes, Contexts, and Consequences (ed. R. D. E. MacPhee). New York: KluwerAcademic/Plenum, pp. 105–43.

Alroy, J. 2000. An ecologically realistic simulation of North America’s end-Pleistocene megafaunalmass extinction. Journal of Vertebrate Paleontology 20, Supplement 3: Abstracts of Papers, SixtiethAnnual Meeting, Mexico City, 25–8 October, p. 26A.

Alvard, M. S. 1998. Evolutionary ecology and resource conservation. Evolutionary Anthropology,7: 62–74.

Ammann, B., Birks, H. J. B., Brooks, S. J., Eicher, U., von Grafenstein, U., Hofmann, W., Lemdahl,G., Schwander, J., Toboslki, K. and Wick, L. 2000. Quanti�cation of biotic responses to rapidclimatic changes around the Younger Dryas: a synthesis. Palaeogeography, Palaeoclimatology,Palaeoecology, 159(3–4): 3, 13–47.

Barlow, C. 2001. The Ghosts of Evolution: Nonsensical Fruits, Missing Partners, and Other EcoIog-ical Anachronisms. New York: Basic Books.

Barnes, R. F. W. and Jensen, K. L. 1987. How to Count Elephants in Forests. African Elephant andRhino Specialist Group Technical Bulletin Number 1.

Bell, R. H. V. 1971. A grazing ecosystem in the Serengeti. Scienti�c American, 225: 86–93.

Bennett, K. D., Haberle, S. G. and Lumley, S. H. 2000. The Last Glacial-Holocene transition insouthern Chile. Science, 290: 325–8.

Bonnichsen, R. and Turnmire, K. L. (eds) 1991. Clovis: Origins and Adaptations. Corvallis, OR:Oregon State University Press for the Center for the Study of the First Americans.

Brush, N. and Smith, F. 1994. The Martins Creek mastodon: a Paleoindian butchery site in HolmesCounty, Ohio. Current Research in the Pleistocene, 1: 14–15.

Brush, N. and Yerkes, R. W. 1996. Microwear analysis of chipped stone tools from the Martins Creekmastodon site, Holmes County, Ohio. Current Research in the Pleistocene, 13: 55–7.

Brush, N., Newman, M. and Smith, F. 1994. Immunological analysis of �int �akes from the MartinsCreek mastodon site. Current Research in the Pleistocene, 11: 16–18.

Catlin, G. (ed. P. Matthiessen) 1989[1844]. North American Indians (original title Letters and Noteson the Manners, Customs and Conditions of the North American Indians Written During Eight Years’Travel (1832–1839) Amongst the Wildest Tribes of Indians of North America). New York: Viking Press.

Charnov, E. L. 1976. Optimal foraging: the marginal value theorem. Theoretical Population Biology,9: 129–36.

Clark, C. W. 1973. The economics of over-exploitation. Science, 181: 630–4.

De Boer, W. F., Ntumi, C. P., Correia, A. U. and Mafuca, J. M. 2000. Diet and distribution ofelephant in the Maputo Elephant Reserve, Mozambique. African Journal of Ecology, 38: 188–201.

Dent, R. J., Jr. 1995. Chesapeake Prehistory: Old Traditions, New Directions. New York: Plenum.

Dincauze, D. F. 1993. Fluted points in the eastern forests. In From Kostenki to Clovis: Upper Pale-olithic – Paleo-Indian Adaptations (eds O. Soffer and N. D. Praslov). New York: Plenum, pp. 279–92.

410 Gary Haynes

Dixon, E. J. 1993. Quest for the Origins of the First Americans. Albuquerque, NM: University ofNew Mexico Press.

Dreimanis, A. 1967. Mastodons, their geological age and extinction in Ontario, Canada. CanadianJournal of Earth Sciences, 4: 663–75.

Duckler, G. L. and van Valkenburgh, B. 1998. Exploring the health of late Pleistocene mammals:the use of Harris lines. Journal of Vertebrate Paleontology, 18(1): 180–8.

Dudley, J. P. 1999. Seed dispersal of Acacia erioloba by African bush elephants in Hwange NationalPark, Zimbabwe. African Journal of Ecology, 37(4): 375–85.

Duffy, K. 1984. Children of the Forest. New York: Dodd, Mead.

Eaton, S. B., Eaton, S. B. III and Konner, J. M. 1997. Paleolithic nutrition revisited: a twelve yearretrospective on its nature and implications. European Journal of Clinical Nutrition, 51: 207–16.

Edwards, S. W. 1992. Observations on the prehistory and ecology of grazing in California.Fremontia, 20(1): 3–11.

Fiedel, S. J. 1999. Older than we thought: implications of corrected dates for Paleoindians. AmericanAntiquity, 64: 95–116.

Fiedel, S. J. 2000. The peopling of the New World: Present evidence, new theories and future direc-tions. Journal of Archaeological Research, 8(1): 39–103.

Fisher, D. C. 1996. Extinction of proboscideans in North America. In The Proboscidea: Evolutionand Palaeoecology of Elephants and their Relatives (eds J. Shoshani and P. Tassy). Oxford: OxfordUniversity Press, pp. 296–315.

Fisher, J. W., Jr. 1987. Shadows in the forest: ethnoarchaeology among the Efe Pygmies. Doctoraldissertation, Department of Anthropology, University of California, Berkeley.

Fisher, J. W., Jr. 1992. Observations of the late Pleistocene bone assemblage from the LambSpring site, Colorado. In Ice Age Hunters of the Rockies (eds D. J. Stanford and J. S. Day).Denver and Niwot, CO: Denver Museum of Natural History and University Press of Colorado,pp. 51–82.

Giraldeau, L. A. 1997. The ecology of information use. In Behavioural Ecology: An EvolutionaryApproach, 4th edn (eds J. R. Krebs and N. B. Davis). Oxford: Blackwell, pp. 42–68.

Graham, R. W. and Lundelius, E. L. Jr. 1984. Coevolutionary disequilibrium and Pleistocene extinc-tions. In Quaternary Extinctions: A Prehistoric Revolution (eds P. S. Martin and R. G. Klein).Tucson, AZ: University of Arizona Press, pp. 223–49.

Graham, R. W., Lundelius, E. L., Jr., Graham, M. A., Schroeder, E. K., Toomey, R. S. III, Anderson,E., Barnosky, A. D., Burns, J. A., Churcher, C. S., Grayson, D. K., Guthrie, R. D., Harington, C.R., Jefferson, G. T., Martin, L. D., McDonald, H. G., Morlan, R. E., Semken, H. A. Jr., Webb, S.D., Werdelin, L. and Wilson, M. C. 1996. Spatial response of mammals to late Quaternary environ-mental �uctuations. Science, 272: 1601–6.

Graham, R. W., Stafford, T. W. Jr. and Semken, H. A. Jr. 1997. Pleistocene extinctions: chronology,non-analog communities, and environmental change. Paper presented at the American Museum ofNatural History, at the Center for Biodiversity and Conservation’s Spring Symposium, 17–18 April,Humans and Other Catastrophes: Explaining Past Extinctions and the Extinction Process, NewYork City.

Gramly, R. M. 1991. Blood residues upon tools from the East Wenatchee Clovis site, DouglasCounty, Washington. Ohio Archaeologist, 41(4): 4–9.

Gramly, R. M. 1993. The Richey Clovis Cache: Earliest Americans aIong the Columbia River.Buffalo, NY: Persimmon Press Monographs in Archaeology.

Guthrie, R. D. 1984. Mosaics, allelochemics and nutrients: an ecological theory of late Pleistocene

Catastrophic extinction of mammoths and mastodonts 411

megafaunal extinctions. In Quaternary Extinctions (eds P. S. Martin and R. G. Klein). Tucson, AZ:University of Arizona Press, pp. 259–98.

Hamilton, T. D. and Goebel, T. 1999. Late Pleistocene peopling of Alaska. In Ice Age Peoples ofNorth America: Environments, Origins, and Adaptations of the First Americans (eds R. Bonnichsenand K. L. Turnmire). Corvallis, OR: Oregon State University Press for the Center for the Study ofthe First Americans, pp. 156–99.

Harris, J. M. and Jefferson, G. T. (eds) 1985. Rancho La Brea: Treasures of the Tar Pits. NaturaIHistory Museum of Los Angeles County Science Series 31.

Haynes, C. V., Jr. 1984. Stratigraphy and late Pleistocene extinction in the United States. In Quater-nary Extinctions: A Prehistoric Revolution (eds P. S. Martin and R. G. Klein). Tucson, AZ:University of Arizona Press, pp. 353–65.

Haynes, C. V., Jr. 1987. Clovis origin update. The Kiva, 52: 83–93.

Haynes, C. V., Jr. 1991. Geoarchaeological and paleohydrological evidence for a Clovis-age droughtin North America and its bearing on extinction. Quaternary Research, 35: 438–50.

Haynes, C. V., Jr. 1993. Clovis-Folsom geochronology and climatic change. In From Kostenki toClovis: Upper Paleolithic – Paleo-Indian Adaptations (eds O. Soffer and N. D. Praslov). New York:Plenum, pp. 219–36.

Haynes, G. 1987. Where elephants die. NaturaI History, 96(6): 28–33.

Haynes, G. 1988. Longitudinal studies of African elephant death and bone deposits. Journal ofArchaeologicaI Science, 15: 131–57.

Haynes, G. 1989. Late Pleistocene mammoth utilization in northeast Asia and North America.Archaeozoologia, 3(1,2): 81–108.

Haynes, G. 1991. Mammoths, Mastodonts, and Elephants: Biology, Behavior, and the Fossil Record.New York: Cambridge University Press.

Haynes, G. 1999. The role of mammoths in rapid Clovis dispersal. In Mammoths and the MammothFauna: Studies of an Extinct Ecosystem (eds G. Haynes, J. Klimowicz and J. W. F. Reumer). Deinsia,6: 9–38.

Haynes, G. and Eiselt, B. S. 1999. The power of Pleistocene hunter-gatherers: forward and backwardsearching for evidence about mammoth extinction. In Extinctions in Near Time: Causes, Contexts,and Consequences (ed. R. D. E. MacPhee). New York: Kluwer Academic/Plenum, pp. 71–93.

Heinrich, B. 1991. Ravens in Winter. New York: Vintage Books.

Heinrich, B. 1999. Mind of the Raven: Investigations and Adventures with Wolf-Birds. New York:Cliff Street Books.

Hester, J. J. 1972. Blackwater Locality No. 1: A Strati�ed, Early Man Site in Eastern New Mexico.Fort Burgwin Research Center (Southern Methodist University) Publication No. 8.

Holliday, V. T. 1997. Paleoindian Geoarchaeology of the Southern High Plains. Austin, TX:University of Texas Press.

Holliday, V. T. 2000. The evolution of Paleoindian geochronology and typology on the Great Plains.Geoarchaeology , 15(3): 227–90.

Hoppe, K. A., Carlson, R. W. and Webb, S. D. 1999. Tracking mammoths and mastodons: recon-struction of migratory behavior using strontium isotope ratios. Geology, 27(5): 439–42.

Hyland, D. C., Tersak, J. M., Adovasio, J. M. and Siegel, M. I. 1990. Identi�cation of the species oforigin of residual blood on lithic material. American Antiquity, 55(1): 104–12.

Janzen, D. H. and Martin, P. S. 1982. Neotropical anachronisms: the fruits the gomphotheres ate.Science, 215: 19–27.

412 Gary Haynes

Jennings, J. D. 1989. Prehistory of North America, 3rd edn. Mountain View, CA: May�eld Publishing.

Johns, T., Mahunnah, R. L. A., Sanaya, P., Chapman, L. and Ticktin, T. 1999. Saponins and phenoliccontent in plant dietary additives of a traditional subsistence community, the Batemi of Ngoron-goro District, Tanzania. Journal of Ethnopharmacology, 66: 1–10.

Johns, T., Nagarajan, M., Parkipuny, M. L. and Jones, P. J. H. 2000. Maasai gummivory: implicationsfor paleolithic diets and contemporary health. Current Anthropology, 41(3): 453–9.

Kay, C. E. 1994. Aboriginal overkill: the role of Native Americans in structuring western ecosys-tems. Human Nature, 5(4): 359–98.

Kay, C. E. 1995. Aboriginal overkill and native burning: implications for modern ecosystemmanagement. Western Journal of Applied Forestry, 10(4): 120–6.

Kelly, R. C. and Todd, L. C. 1988. Coming into the country: early Paleoindian hunting and mobility.American Antiquity, 53: 231–44.

King, J. E. and Saunders, J. J. 1984. Environmental insularity and the extinction of the Americanmastodont. In Quaternary Extinctions: A Prehistoric Revolution (eds P. S. Martin and R. G. Klein).Tucson, AZ: University of Arizona Press, pp. 315–44.

Koch, P. L., Hoppe, K. A. and Webb, S. D. 1998. The isotopic ecology of late Pleistocene mammalsin North America – Part 1. Florida. Chemical Geology, 152(1–2): 119–38.

Kooyman, B., Tolman, S., Hills, L. V. and McNeil, P. 2000. The archaeological context of late Pleisto-cene remains from the Wally’s Beach site, Alberta. Paper presented at the 65th Annual Meeting ofthe Society for American Archaeology. Society for American Archaeology Abstracts of the 65thAnnual Meeting, 5–9 April Philadelphia, PA.

Krech, S., III. 1999. The Ecological Indian: Myth and History. New York: Norton.

Laub, R. S. 1994. The Pleistocene/Holocene transition in western New York state: fruits of inter-disciplinary studies at the Hiscock site. In Great Lakes ArchaeoIogy and Paleoecology: ExpIoringInterdisciplinary Initiatives for the Nineties (ed. R. I. MacDonald). Waterloo, Ontario: The Quater-nary Sciences Institute, University of Waterloo, pp. 155–67.

Laub, R. S. and Haynes, G. 1998. Fluted points, mastodons, and evidence of late-Pleistocenedrought at the Hiscock site, western New York state. Current Research in the Pleistocene, 15: 32–4.

Laub, R. S., Miller, N. G. and Steadman, D. W. (eds) 1988. Late Pleistocene and Early HolocenePaleoecology and Archeology of the Eastern Great Lakes Region. BuIletin of the Buffalo Society ofNatural Sciences 33.

Laub, R. S., Dufort, C. A. and Christenson, D. J. 1994. Possible mastodon gastrointestinal and fecalcontents from the late Pleistocene of the Hiscock site, western New York state. In Studies in Stratig-raphy and Paleontology in Honor of Donald W. Fisher (ed. E. Landing). New York State MuseumBulletin 481, pp. 135–48.

Laws, R. M., Parker, I. S. C. and Johnstone, R. C. B. 1975. Elephants and Their Habitats: TheEcology of Elephants in North Bunyoro, Uganda. Oxford: Clarendon Press.

Lee, R. B. 1968. What hunters do for a living, or, how to make out on scarce resources. In Man theHunter (eds R. B. Lee and I. DeVore). Chicago: Aldine, pp. 30–48.

Lincoln, R. J. and Boxshall, G. A. 1987. The Cambridge Illustrated Dictionary of Natural History.Cambridge: Cambridge University Press.

Loy, T. H. and Dixon, E. J. 1998. Blood residues on �uted points from eastern Beringia. AmericanAntiquity, 63: 21–46.

McAvoy, J. M. and McAvoy, L. D. 1997. Archaeological Investigations of Site 44SX202, Cactus Hill,Sussex County, Virginia. Virginia Department of Historic Resources, Research Report Series No.8.

Catastrophic extinction of mammoths and mastodonts 413

MacDonald, G. F. 1968. Debert: A Palaeo-Indian Site in Central Nova Scotia. National Museums ofCanada Anthropology Papers No. 16.

Martin, P. S. 1967. Prehistoric overkill. In Pleistocene Extinctions: The Search for a Cause (eds P. S.Martin and H. E. Wright). New Haven, CT: Yale University Press, pp. 75–120.

Martin, P. S. 1982. The pattern and meaning of Holarctic mammoth extinction. In Paleoecology ofBeringia (eds D. M. Hopkins, J. V. Mathews, C. E. Schweger and S. B. Young). New York: AcademicPress, pp. 399–408.

Martin, P. S. 1984. Prehistoric overkill: the global model. In Quaternary Extinctions: A PrehistoricRevolution (eds P. S. Martin and R. G. Klein). Tucson, AZ: University of Arizona Press, pp.354–403.

Martin, P. S. 1990. 40,000 years of extinctions on the ‘planet of doom’. Palaeogeography, Palaeo-climatology, Palaeoecology, 82: 187–201.

Martin, P. S. and Klein, R. G. (eds) 1984. Quaternary Extinctions: A Prehistoric Revolution. Tucson,AZ: University of Arizona Press.

Martin, P. S. and Steadman, D. W. 1999. Prehistoric extinctions on islands and continents. In Extinc-tions in Near Time: Causes, Contexts, and Consequences (ed. R. D. E. MacPhee). New York: KluwerAcademic/Plenum, pp. 17–55.

Martin, P. S. and Stuart, A. J. 1995. Mammoth extinction: two continents and Wrangel Island. Radio-carbon, 37(1): 7–10.

Meltzer, D. J. 1988. Late Pleistocene human adaptations in Eastern North America. Journal ofWorld Prehistory, 2: 1–53.

Meltzer, D. J. 1993. Is there a Clovis adaptation? In From Kostenki to Clovis: Upper Paleolithic –Paleo-Indian Adaptations (eds O. Soffer and N. D. Praslov). New York: Plenum, pp. 293–310.

Meltzer, D. J. and Smith B. D. 1986. Paleoindian and Early Archaic subsistence strategies in easternNorth America. In Foraging, Collecting and Harvesting: Archaic Period Subsistence and Settlementin the Eastern Woodlands (ed. S. W. Neusius). Center for Archaeological Investigations OccasionalPaper 6. Carbondale: Southern Illinois University, pp. 3–31.

Mithen, S. 1993. Simulating mammoth hunting and extinction: implications for the late Pleistoceneof the central Russian Plain. In Hunting and Animal Exploitation in the Later Palaeolithic andMesolithic of Eurasia (eds G. L. Peterkin, H. M. Bricker and P. Mellars). Anthropological Papersof the American Anthropological Association, Number 4, pp. 163–78.

Molyneaux, B. L. 2000. Update on the Northern Loess Hills Clovis Point. Newsletter of the IowaArchaeological Society, 50(4): 1–2

Owen-Smith, R. N. 1982. Dispersal and the dynamics of large herbivores in enclosed areas: impli-cations for management. In Management of Large Mammals in African Conservation Areas (ed. R.N. Owen-Smith). Pretoria: HAUM Educational Publishers, pp. 127–40.

Owen-Smith, R. N. 1987. Pleistocene extinctions: the pivotal role of megaherbivores. Paleobiology,13: 351–62.

Owen-Smith, R. N. 1988. Megaherbivores: The In�uence of Very Large Body Size on Ecology.Cambridge: Cambridge University Press.

Owen-Smith, R. N. 1999. The interaction of humans, megaherbivores, and habitats in the latePleistocene extinction event. In Extinctions in Near Time: Causes, Contexts, and Consequences (ed.R. D. E. MacPhee). New York, Kluwer Academic/Plenum, pp. 57–69.

Putschkov, P. V. 1997. Were the mammoths killed by the warming? Testing the climatic versions ofWürm extinctions. Vestnik Zoologii (Journal of the Schmalhausen lnstitute of Zoology, NationalAcademy of Sciences, Ukraine).

414 Gary Haynes

Rachlow, J. L. 1997. Demography, behavior, and conservation of white rhinos. Doctoral disser-tation, Program in Evolution, Ecology, and Conservation Biology, University of Nevada, Reno.

Rachlow, J. L., Berkeley, E. V. and Berger, J. 1998. Correlates of male mating strategies in whiterhinos (Ceratotherium simum). Journal of Mammalogy, 79: 1317–24.

Richards, M. P., Hedges, R. E. M., Jacobi, R., Current, A. and Stringer, C. 2000. FOCUS: Gough’sCave and Sun Hole Cave human stable isotope values indicate a high animal protein diet in theBritish Upper Palaeolithic. Journal of ArchaeologicaI Science, 27: 1–3.

Rodbell, D. T. 2000. The Younger Dryas: cold, cold everywhere? Science, 290: 285–6.

Rutter, N. W., Weaver, A. J., Rokosh, D., Fanning, A. F. and Wright, D. G. 2000. Data-modelcomparison of the Younger Dryas event. Canadian Journal of Earth Sciences, 37: 811–30.

Sealy, J. and Pfeiffer, S. 2000. Diet, body size, and landscape use among Holocene people in thesouthern Cape, South Africa. Current Anthropology, 41(4): 642–55.

Sikes, S. K. 1971. The Natural History of the African Elephant. New York: American Elsevier.

Smith, E. A. and Wishnie, M. 2000. Conservation and subsistence in small-scale societies. AnnualReview of Anthropology, 29: 493–524.

Speth, J. D. and Spielmann, K. 1983. Energy source, protein metabolism, and hunter-gatherersubsistence strategies. Journal of Anthropological Archaeology, 2: 1–31.

Spiess, A. and Wilson D. B. 1987. Michaud: A Paleoindian Site in the New England-MaritimesRegion. Maine Archaeological Society Occasional Publications in Maine Archaeology 6.

Stafford, T. W., Jr. 1988. Accelerator 14C dating of late Pleistocene megafauna. Current Researchin the Pleistocene, 5: 41–3.

Stafford, T. W., Jr. 1999. Chronologies for the oldest human skeletons in the New World. GeologicalSociety of America, 31(7)(Annual Meeting, Abstracts with Program): 24.

Stafford, T. W., Jr., Jull, A. J. T., Brendel, K., Duhamel, R. C. and Donahue, D. 1987. Study of boneradiocarbon dating accuracy at the University of Arizona NSF Accelerator Facility for Radio-isotope Analysis. Radiocarbon, 29(1): 24–44.

Stafford, T. W., Jr., Brendel, K. and Duhamel, R. C. 1988. Radiocarbon, 13C and 15N analysis offossil bone: removal of humates with XAD-2 resin. Geochimica et Cosmochimica Acta, 52: 2257–67.

Stafford, T. W., Jr., Graham, R. W., Semken, H. A., Jr. and Southon, J. 1997a. AMS 14C chronolo-gies for late Pleistocene mammal extinctions and human migrations in North America. Abstractsof 1997 CAVEPS (on-line: <http: //bioscience.babs.unsw.edu.au/CAVE T.htm>), University of NewSouth Wales.

Stafford, T. W., Jr., Graham, R. W., Semken, H. A., Jr. and Southon, J. 1997b. Chronology andtiming of the terminal Pleistocene extinction event in the mid-latitudes of North America. Paperpresented at 7th International Theriological Congress, Acapulco, Mexico.

Stock, C. 1972. Rancho La Brea: A Record of Pleistocene Life in California, 6th edn. Los AngelesCounty Museum of Natural History Science Series No. 20, Paleontology, No. 11.

Stone, R. 1998. A bold plan to re-create a long-lost Siberian ecosystem. Science, 282: 31–4.

Stuart, A. J. 1991. Mammalian extinctions in the late Pleistocene of northern Eurasia and NorthAmerica. Biological Reviews, 66: 453–562.

Stuart, A. J. 1999. Late Pleistocene megafaunal extinctions: a European perspective. In Extinctionsin Near Time: Causes, Contexts, and Consequences (ed. R. D. E. MacPhee). New York: KluwerAcademic/Plenum, pp. 257–69.

Sullivan, R. 2000. A Whale Hunt. New York: Scribner.

Catastrophic extinction of mammoths and mastodonts 415

Taylor, R. E., Haynes, C. V., Jr. and Stuiver, M. 1996. Clovis and Folsom age estimates: stratigraphiccontext and radiocarbon calibration. Antiquity, 70(269): 515–25.

Theuerkauf, J. and Ellenberg, H. 2000. Movements and defaecation of forest elephants in the moistsemi-deciduous Bossematié Forest Reserve, Ivory Coast. African Journal of Ecology, 38(3): 258–61.

Webster, D. and Webster, G. 1984. Optimal hunting and Pleistocene extinction. Human Ecology,12: 275–89.

Western, D. 1989. The ecological value of elephants: a keystone role in African ecosystems. In TheIvory Trade and the Future of the African Elephant, Vol. 2, Section 5.2 (co-ordinator S. Cobb).Oxford: The Ivory Trade Review Group.

Western, D. 1991. When the forest falls silent. In Elephants: The Deciding Decade (ed. R.Orenstein). Toronto, Ontario: Key Porter, pp. 83–95.

Willey, G. R. 1966. An Introduction to American Archaeology, Vol. 1, North and Middle America.Englewood Cliffs, NJ: Prentice-Hall.

Winterhalder, B. 1981. Optimal foraging strategies and hunter-gatherer research in anthropology:theory and models. In Hunter-Gatherer Foraging Strategies: Ethnographic and ArchaeologicalAnalyses (eds B. Winterhalder and E. A. Smith). Chicago: University of Chicago Press, pp. 13–35.

Yesner, D. R. 1980. Maritime hunter-gatherers: ecology and prehistory. Current Anthropology, 21:727–50.

Zimov, S. A., Chuprynin, V. I., Oreshko, A. P., Chapin, F. S. III, Reynolds, J. F. and Chapin, M. C.1995. Steppe-tundra transition: a herbivore-driven biome shift at the end of the Pleistocene.American Naturalist, 146: 765–94.

416 Gary Haynes